Forums Technical Discussion how to best find overlapping pts on differing prims?

how to best find overlapping pts on differing prims?

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Dougie0047
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Hello Houdini community,

I have a problem where I am trying to find a good method of procedurally find points that overlap in space, but are not connected and belong to different primitives.

Specifically, I am cutting a circle (polyline) into sections with the labs boolean curve tool, but due to how the circle is scaled, oriented etc. as well as it being an open polyline curve I am ending up with one or more places with overlapping, unconnected points in places where I do not want the points to be unconnected. The attached image should give you a better idea of what I mean.

I need to find these points so that I can fuse them before I then can use something like the convert line node to create a single primitive per section. I have found a way to do this under certain conditions, but my way only finds one instance and it turns out that there could be multiple instances of this happening and at that point my current method fails.

Do you have any idea as to what would be the best method for doing this?

Thanks,

Dag

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unconnected_pts_on_diff_prims_issue.png (118.8 KB)

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mawi
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You should be able to do this with the fuse node.
1. create a s@name for each prim
2. Set it to only get unequal attributes.
3. output groups

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snap.png (84.4 KB)

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animatrix_
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Hi,

You can do this in VEX easily:

int pts [ ] = pcfind ( 0, "P", @P, ch("radius"), chi("maxpts") );
removevalue ( pts, @ptnum );

if ( len ( pts ) > 0 )
{
    int primid = pointprims ( 0, pts [ 0 ] ) [ 0 ];
    if ( primid != @primnum )
        i@group_overlap = 1;
}

Senior FX TD @ Industrial Light & Magic
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Dougie0047
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@mawi and animatrix: Thanks for your suggestions! I'll give both of those a try as soon as I can
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